CDMA (Code Division Multiple Access, referred to as CDMA) network provides services to a number of operators worldwide. As shown in FIG. 1, CDMA2000 network consists of the core network and the radio access network, wherein, the core network mainly consists of a mobile switching center (MSC), a visited location register (VLR), and a Home Location Register (HLR); the radio access network mainly consists of base station controllers (BSCs) and base transceiver stations (BTSs). The interface between the BSC and the MSC is known as A1/A2, A1 mainly refers to the control plane interface, and A2 mainly refers to the media plane interface (the interface A1/A2 sometimes is referred to as A interface in the field); the interface between the BSC and the BTS is called interface Abis, the interface between the BSCs is called interface A3/A7. CDMA2000 network can also provide packet data service, and the BSC connects with the Packet Control Function (referred to as PCF) via the interfaces A8 and A9, and the PCF connects with the packet data service node (referred to as PDSN) via the interfaces A10 and A11. With the IP-based evolution of CDMA2000 networks and the introduction of the concept soft switch, the interface A1/A2 can be replaced to IP mode from the traditional E1/T1 connectivity, FIG. 2 shows the networking when using the IP technology, where the MSC is split into two network elements: the mobile switching center emulation (MSCe) and the Media Gateway (MGW) dealing with control plane and media streaming respectively. The interface between the BSC and the MSCe is called interface Alp, and the interface between the BSC and the MGW is called interface A2p (similar to the interface A, the interface A1p/A2p is sometimes referred to as interface Ap).
Due to reasons such as the evolution of CDMA2000 networks, subscriber growth, and operator business strategy, sometimes it needs to replace or upgrade some network elements or equipments in the existing network or to change the connection relationship between the network elements and the equipments. For example, sometimes it needs to replace the core network, that is, update the core network equipment without changing the radio network. This requires cutting over the interfaces A1 and A2 in CDMA2000 networks, that is, disconnecting the BSC from the current MSC/MSCe and then connecting it to another new MSC/MSCe. For another example, sometimes it needs to transfer the BTS from one BSC to another BSC to reduce the burden of the current BSC or replace the BTS with a new BSC. For still another example, sometimes it needs to upgrade the interface A to the interface Ap to enjoy various advantages brought by applying the packet switching technology into the CDMA2000 network.
Generally, the operation of changing the connection relationship between network elements or equipments or replacing the network elements is called cutover in the field. In the equipment cutover or replacement process, the commonly used method is to disconnect the old connection, and then create a new connection. Because this process involves the disconnection and reconnection in the control plane and the media plane, the user services will inevitably be interrupted. The Chinese invention patent application whose application number is 200810004333.6 discloses a method and device for reducing the service interruption interval in the service cutover process, but the method still has the “service interruption” issue. Service interruption inevitably brings some negative effects and reduces the user's satisfaction. Despite the cutover process can be controlled in the shortest possible time and with minimized impact on users with careful planning and thorough preparation, this short break sometimes is difficult to accept with the increasing user requirements.